---
title: "execute_sql"
---

Execute SQL queries and statements on your database with support for transactions, multiple statements, and safety controls.

## Features

- **Single statements**: Execute a single SQL query or command
- **Multiple statements**: Separate multiple statements with semicolons (`;`)
- **Transactions**: Wrap operations in `BEGIN`/`COMMIT` blocks for atomic execution
- **Read-only mode**: When enabled with `--readonly` flag, only SELECT and read-only operations are allowed
- **Row limiting**: Configure `--max-rows` to limit SELECT query results

## Single Query

Execute a single SELECT, INSERT, UPDATE, or DELETE statement.

<CodeGroup>
```sql SELECT
SELECT * FROM users WHERE status = 'active' LIMIT 10;
```

```sql INSERT
INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com');
```

```sql UPDATE
UPDATE users SET last_login = NOW() WHERE id = 123;
```

```sql DELETE
DELETE FROM sessions WHERE expires_at < NOW();
```
</CodeGroup>

## Multiple Statements

Execute multiple SQL statements in sequence by separating them with semicolons.

```sql
INSERT INTO users (name, email) VALUES ('Alice', 'alice@example.com');
INSERT INTO users (name, email) VALUES ('Bob', 'bob@example.com');
INSERT INTO users (name, email) VALUES ('Charlie', 'charlie@example.com');
```

<Note>
Each statement is executed sequentially. If one statement fails, subsequent statements may not be executed depending on the database error handling.
</Note>

## Transactions

Wrap multiple operations in a transaction to ensure atomicity. Use `BEGIN`/`COMMIT` for successful transactions or `ROLLBACK` to undo changes.

<CodeGroup>
```sql Successful Transaction
BEGIN;
UPDATE accounts SET balance = balance - 100 WHERE id = 1;
UPDATE accounts SET balance = balance + 100 WHERE id = 2;
COMMIT;
```

```sql Rollback Transaction
BEGIN;
UPDATE accounts SET balance = balance - 100 WHERE id = 1;
-- Something went wrong, undo changes
ROLLBACK;
```
</CodeGroup>

## DDL Operations

Create, alter, or drop database objects.

<CodeGroup>
```sql CREATE TABLE
CREATE TABLE products (
  id SERIAL PRIMARY KEY,
  name VARCHAR(255) NOT NULL,
  price DECIMAL(10, 2) NOT NULL,
  created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
```

```sql ALTER TABLE
ALTER TABLE products ADD COLUMN category VARCHAR(100);
```

```sql CREATE INDEX
CREATE INDEX idx_products_category ON products(category);
```

```sql DROP TABLE
DROP TABLE IF EXISTS temp_data;
```
</CodeGroup>

## Read-Only Mode

Restrict SQL execution to safe, read-only operations by configuring the `execute_sql` tool with `readonly = true`:

<CodeGroup>
```toml TOML Configuration
[[sources]]
id = "production"
dsn = "postgres://user:pass@localhost:5432/mydb"

[[tools]]
name = "execute_sql"
source = "production"
readonly = true
```

```bash Command Line (Deprecated)
# This flag is deprecated - use TOML configuration instead
npx @bytebase/dbhub --readonly --dsn "postgres://user:pass@localhost:5432/mydb"
```
</CodeGroup>

In read-only mode, only [allowed SQL keywords](https://github.com/bytebase/dbhub/blob/main/src/utils/allowed-keywords.ts) are permitted, including:

- `SELECT` queries
- `SHOW` commands
- `DESCRIBE` commands
- `EXPLAIN` queries
- Other read-only operations

## Row Limiting

Limit the number of rows returned from SELECT queries to prevent accidentally retrieving too much data:

<CodeGroup>
```toml TOML Configuration
[[sources]]
id = "production"
dsn = "postgres://..."

[[tools]]
name = "execute_sql"
source = "production"
max_rows = 1000
```

```bash Command Line (Deprecated)
# This flag is deprecated - use TOML configuration instead
npx @bytebase/dbhub --max-rows 1000 --dsn "..."
```
</CodeGroup>

- Only applied to SELECT statements, not INSERT/UPDATE/DELETE
- If your query already has a `LIMIT` or `TOP` clause, DBHub uses the smaller value
- Can be configured per-tool in [multi-database TOML configuration](/config/multi-database)

## Selective Tool Exposure

Control which tools are available for each database source. By default, both `execute_sql` and `search_objects` are enabled. You can:

- Disable built-in tools entirely
- Configure specific tools with custom settings
- Expose only custom tools for restricted access

**Example: Disable execute_sql, keep search_objects:**

```toml
[[sources]]
id = "production"
dsn = "postgres://..."

# Only enable search_objects - execute_sql will not be available
[[tools]]
name = "search_objects"
source = "production"
```

**Example: Read-only execute_sql with row limit:**

```toml
[[sources]]
id = "production"
dsn = "postgres://..."

[[tools]]
name = "execute_sql"
source = "production"
readonly = true
max_rows = 100

[[tools]]
name = "search_objects"
source = "production"
```

<Note>
If no `[[tools]]` entries are defined for a source, both `execute_sql` and `search_objects` are enabled by default for backward compatibility.
</Note>
